docs: def findTransformation(self, inSR, outSR, extentOfInterest=None, numOfResults=1):
          """
          The findTransformations operation is performed on a geometry
          service resource. This operation returns a list of applicable
          geographic transformations you should use when projecting
          geometries from the input spatial reference to the output spatial
          reference. The transformations are in JSON format and are returned
          in order of most applicable to least applicable. Recall that a
          geographic transformation is not needed when the input and output
          spatial references have the same underlying geographic coordinate
          systems. In this case, findTransformations returns an empty list.
          Every returned geographic transformation is a forward
          transformation meaning that it can be used as-is to project from
          the input spatial reference to the output spatial reference. In the
          case where a predefined transformation needs to be applied in the
          reverse direction, it is returned as a forward composite
          transformation containing one transformation and a transformForward
          element with a value of false.
  
          Inputs:
             inSR - The well-known ID (WKID) of the spatial reference or a
               spatial reference JSON object for the input geometries
             outSR - The well-known ID (WKID) of the spatial reference or a
               spatial reference JSON object for the input geometries
             extentOfInterest - The bounding box of the area of interest
               specified as a JSON envelope. If provided, the extent of
               interest is used to return the most applicable geographic
               transformations for the area. If a spatial reference is not
               included in the JSON envelope, the inSR is used for the
               envelope.
             numOfResults - The number of geographic transformations to
               return. The default value is 1. If numOfResults has a value of
               -1, all applicable transformations are returned.
          """
          params = {
              "f" : "json",
              "inSR" : inSR,
              "outSR" : outSR
          }
          url = self._url + "/findTransformations"
          if isinstance(numOfResults, int):
              params['numOfResults'] = numOfResults
          if isinstance(extentOfInterest, Envelope):
              params['extentOfInterest'] = extentOfInterest.asDictionary
          return self._post(url=url, param_dict=params,
                               securityHandler=self._securityHandler,
                               proxy_url=self._proxy_url,
                               proxy_port=self._proxy_port)